1. Field of Invention
The invention concerns a lifting tube with a tube wall extending about a lengthwise axis and enclosing a tube interior, the lifting tube can be reversibly deformed along its lengthwise axis into an elongated configuration, and with a reduction of the tube interior (28), into a contracted configuration, as well as a handling device, including a tube lifter, with a lifting tube, having a tube interior, wherein the lifting tube can be shortened by applying a partial vacuum to the tube interior, and with a gripping device connected to one end of the lifting tube.
2. Description of Related Art
Lifting tubes of this kind find use, e.g., in tube lifters. A shortening of the lifting tube produced by a partial vacuum supports the lifting of a grasped object. However, other applications are also conceivable for the lifting tubes, such as the role of pneumatic actuators. Here, the lengthening of the lifting tube caused by excess pressure can exert a force on an object, e.g., for the lifting or moving of loads.
Tube lifters with lifting tubes of the mentioned kind are described, e.g., in WO 2005/110907 A1 or in U.S. Pat. No. 4,413,853. These lifting tubes have a bellows-like configuration with encircling annular creases fashioned alternately as inner creases and outer creases along the axial dimension, or a configuration with a helical crease line encircling in screw fashion the longitudinal axis of the lifting tube. Customarily, a wire skeleton is inserted in the outer creases of the lifting tube, which prevents a radial contraction of the lifting tube. The contraction ratio of such lifting tubes, i.e., the ratio of the axial length in the contracted configuration to the length in the elongated configuration cannot easily be reduced below 25% to 30%, since the material layers lying one on another as a result of the folding of the tube wall along the longitudinal axis and the wire skeleton possibly present in the outer creases require a certain space. Therefore, when using such lifting tubes in a tube lifter a not insignificant total height of the device is needed for a desired lift height.